Google.com gets @45 hits for the "quick and dirty" search: "Great Railway Strike of 1877" baltimore, and a number of them are official history sites like the National Park Service and West Virginia history sites. For example, http://www.cr.nps.gov/nhl/designations/samples/wv/roundhouse.pdf "NATIONAL HISTORIC LANDMARK NOMINATION: The Baltimore and Ohio Railroad Martinsburg Shops" is 58 pages (designated a landmark, July 2003). It has an extended discussion of the strike – click on the .pdf binoculars icon and search: strike.

Likewise, use CTRL-F (find in page) to search: 1877 in http://www.gutenberg.org/files/14458/14458-8.txt

A HISTORY OF TRADE UNIONISM IN THE UNITED STATES BY SELIG PERLMAN, PH.D.Assistant Professor of Economics in the University of Wisconsin;Co-author of the History of Labour in the United States
New York, THE MACMILLAN COMPANY 1922 (Release Date: December 25, 2004 [EBook #14458]PROJECT GUTENBERG E-BOOK A HISTORY OF TRADE UNIONISM
Produced by William Boerst, Martin Pettit and the PG Online Distributed Proofreading Team)
You will need to click several times to get to the 1877 that is in the part of this book that discusses the B&O strike.
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One step above this search would be http://scholar.google.com , to get more "official" studies of this strike.
The search: B&O 1877 strike gets 5 hits; B&O 1877 blacks gets 4 hits; 1877 "railroad strike" racial gets @30 hits, etc.

I found only a few leads in www.maryland.gov , mainly this one: "The Baltimore Railroad Strike & Riot of 1877". Archives of Maryland series: Documents for the Classroom. Maryland State Archives,350 Rowe Boulevard, Annapolis, MD 21401. Phone: (410) 260-6400 Internet:
http://www.mdarchives.state.md.us . e-mail: archives@mdarchives.state.md.us
http://www.mdarchives.state.md.us/msa/speccol/sc2200/sc2221/000009/html/0016.html
This site requires registration for a password to see the apparently extensive full text online accounts of the Great Strike.

West Virginia Division of Culture and History has a search page at:
http://www.wv.gov/OffSite.aspx?u=http://www.wvculture.org/search.aspx
If you search "All Words": 1877 strike, you get many hits, but it appears to me they generally list articles in their journal"West Virginia History", or holdings in archives, so you would either need to order copies online for a fee, or contact the various archives about getting copies.

I find very little more online on the Great Railway Strike. You may very well want to look further in library collections, under the subject words: Railroad strikes 1877 (27 hits in Worldcat database), or in more general books on labor history and railroad industry history. I was surprised that the Library of Congress "American Memory" site at http://memory.loc.gov does not seem to have much material on this strike.